Is anyone else having serious issues with getting accurate height (altitude) readings with the Phantom 4. I am currently on my 4th Phantom 4 and every single one is reporting height readings that is usually extremely inaccurate. The original Phantom 4 was purchased at a Big Box store and then swapped out under warranty 3 different time all due to the fact that I can't get an accurate reading despite being setup and calibrated properly.

In each case the drone was taken out of the box, firmware updated, and system calibrated. On the very first flight with each new drone the height was incorrect. I have made this known to DJI and even sent a picture to them showing the drone being inches of the ground yet the DJI GO app showing it was 19 ft off the ground. I've been told developers are looking into this, but haven't heard anything.

I am very curious if and how many others are having the same issue. I have seen a number of videos of people experiencing similar issue, but figured I'd go the forum to get some exact feedback. Thanks.

Hello rpmurph83 , barometer performance can be influenced by air pressure and air flow. Also, the altitude number will change when the reference changes.But you don't need to worry about it too much if your drone can hold its attitude and altitude well in the air. In low altitude above the ground, the performance of ultrasonic unit would be better in detecting the height.

Thanks for the reply and I agree with your first sentence. However the measurement is off by a large amount which can mean the difference between crashing into something or not. As seen in the photo provided the app says its 22 ft off the ground when its physically inches off the ground.

The other thing I should mention that in reality is a more serious problems is all 4 brand new Phantom 4's would not hold their height usually when under 10 feet off the ground. If you take off a few feet and then let go over the controls, all four drones would hover in position, but would slowly drop to several inches off the ground.

I have seen similar with My P3A. A couple things. First if you land and shut off the motors, it should reset the Alt to zero and you can take off again. Second, I have not seen the issue much since I started letting the aircraft sit on the ground a little longer before taking off (powered on of course), i.e. a longer warm-up time. Although this is largely conjecture, this may help you and can't hurt.

KM5RG-Robert Posted at 2016-8-24 00:45
I have seen similar with My P3A. A couple things. First if you land and shut off the motors, it shou ...

Your reply makes me think the issue is with more systems than just the P4. As for the trick you mentioned, I noticed that as well and periodically do that to get it to reset. However for such an expensive drone the readings should be much more accurate in my opinion.

rpmurph83 Posted at 2016-8-24 05:25
Thanks for the reply and I agree with your first sentence. However the measurement is off by a large ...

If in doubt refer to the reading from the ultrasonic unit, it says 1 foot from the ground.

What surprises me is that when the VPS (therefore ultrasonic) unit is active at and below 10m (Approx' 33 feet) that its reading is not displayed as the height. The barometer could then supply the data when VPS above its active height.

I'll need to look a little closer next time I'm out and see.  I do remember looking up at the quad and thinking "that sure doesn't look like 15 feet".  I normally do several minutes on the ground for warm-up while checking and fiddling with my tablet but you have me curious.

"But you don't need to worry about it too much if your drone can hold its attitude and altitude well in the air."

Well maybe not, but if you are setting altitude points and positions based on geographical features then you might want to have a relatively accurate approximation at least.

In my opinion all the measurements displayed on the DJI Go App need to be as close to accurate as possible. This is a top of the line drone and inaccuracies such as ones seen in the photo I provided shouldn't be acceptable. If it was a one off issue or something that happened occasionally that would be a different story. But the same issue on 4 different brand new drones tells me there something definitely wrong. But that's just my two cents and I think DJI needs to take provided a fix for this.

rpmurph83 Posted at 2016-8-24 17:29
Your reply makes me think the issue is with more systems than just the P4. As for the trick you me ...

'However for such an expensive drone the readings should be much more accurate in my opinion.'

The cost of the unit has nothing to do with it, the accuracy is a limitation of barometric systems, it happens even in full size aircraft, which use the same system, except they are not trying to measure altitude to within a few feet.

And there is nothing that DJI can really do to correct it, especially as they have not provided any form of specification in terms of measured height accuracy.

That an iPad Mini 2 or a Mini 4? Reason I ask is that a Mini 4 has it's own barometer and it may be reading that instead of the bird's reading. It would explain 4 birds same problem because it's not the bird that's bad it's the barometer calibration in the iPad (and ill behaved software that should read the bird)  Just thinking out loud....

Geebax Posted at 2016-8-24 19:15
'However for such an expensive drone the readings should be much more accurate in my opinion.'

Th ...

I understand where your coming from but cost does play into it. If it was a 20 dollar drone I would expect inaccuracies. Not with a top of the line drone like the Phantom 4.

roger.crawford Posted at 2016-8-24 20:01
That an iPad Mini 2 or a Mini 4? Reason I ask is that a Mini 4 has it's own barometer and it may be  ...

mine is the ipad mini 2. do you have the mini 4 and experience this issue?

roger.crawford Posted at 2016-8-25 10:01
That an iPad Mini 2 or a Mini 4? Reason I ask is that a Mini 4 has it's own barometer and it may be  ...

The DJI software is not interested in the altitude of your iPad, the reading is from the aircraft.

rpmurph83 Posted at 2016-8-25 13:50
I understand where your coming from but cost does play into it. If it was a 20 dollar drone I woul ...

You just don't get it, the technology is not that accurate, and it has nothing to do with DJI. Whether it is a 20 dollar drone or a 2,000 drone, a barometer based system is not very accurate unless you can enter a pressure offset for the starting point of your flight. That is what aircraft pilots have to do, but is far too complex for the people who fly drones to handle. And unfortunately, nothing else is accurate either, except perhaps the ultrasonic distance sensor in the VPS system. GPS is also woefully bad at reporting accurate height, so much so DJI do not use it at all.

I have the same problem

Geebax Posted at 2016-8-25 13:19
The DJI software is not interested in the altitude of your iPad, the reading is from the aircraft.

But... if some lazy coder pulls a value from the tablet instead of the bird... You obviously don't work with dev teams :-)  That said, he has a Mini 2 so it's irrelevant.

rpmurph83 Posted at 2016-8-25 12:10
mine is the ipad mini 2. do you have the mini 4 and experience this issue?

In all honesty I haven't checked. I pay attention to where the drone is in relation to the ground versus what the screen says.

I posted on here I had the same problem with my P3A.  Altitude would drop at a hover, and reading would be inaccurate.  I returned it for another one, that was just slightly better.  I believe (based upon reading here and other forums) that it is also temperature related, which is why letting it sit and adjust to the outdoor temp, or flying, landing and starting again seems to reduce or eliminate the issue.  

Something definitely to keep an eye on, as on one of my flights, it was 37 feet off at landing.  Add some height to your return to home height to accommodate.

roger.crawford Posted at 2016-8-25 22:53
But... if some lazy coder pulls a value from the tablet instead of the bird... You obviously don't  ...

'You obviously don't work with dev teams :-)'

You would be dead wrong there, I have lead development teams in sophisticated software development, and BTW, you don't just accidentally pull an altitide reading from a rablet.

Aardvark Posted at 2016-8-24 04:46
If in doubt refer to the reading from the ultrasonic unit, it says 1 foot from the ground.

What s ...

well if you go over a roof, and it resets the height than that could be a problem, the barometric height is the height above the takeoff point and the drone doesn't know if its above the same surface that it took off from, so it shows its 1 foot from a solid surface and an approximate 9 feet from takeoff, which may be wrong, but the height from takeoff shouldn't have that much of an effect on performance especially with the vps.

rpmurph83 Posted at 2016-8-24 17:54
In my opinion all the measurements displayed on the DJI Go App need to be as close to accurate as po ...

i doubt its something they can fix, its a problem with the technology used, not the hardware. And the p4 is far from top of the line, especially with drones like the inspire 1 pro and raw being sold by the same company, which are far more professional.

I am having the same problem with my P4. It doesn't matter if I am using my Samsung Galaxy S5 or if I am using my fatshark  dominator  V3 my height is terribly wrong. Just as the person above-stated when it's a foot off the ground it's reading approximately 22 to 21 feet. Some people thinks that doesn't seem to matter much  but when you are setting a flight path To video things at a certain height I would believe that  it probably would and could cause a catastrophe if you can't trust your height readings. While checking mine tonight I let it hover and it seemed okay I took it to about 30 feet and  let off the  controls and you can hear it start coming down as if it were landing on its own and  I had to hit the up control to get it to stop. sounds like there's something going on with more than a barometer.

deweyld58@Comca Posted at 2016-8-27 14:59
I am having the same problem with my P4. It doesn't matter if I am using my Samsung Galaxy S5 or if  ...

my point exactly, but everyone is entitled to their own opinions....

I  noticed the other day I am at 19 feet at 3 feet ofF the ground. My tablet is the mini 2. Hovers just fine.

This morning I was out flying and the altitude was right on.  No changes to the system.  Go figure.

I too, am having the same altitude inaccuracies with the P4.  It should be much more accurate.  Explain why it was extremely accurate on my P3 Standard which is a fraction of the cost?? I will be about 3' off the ground and my altitude says -6' or so.  Has been doing this for a couple of months now.  Been flying for years and everything is calibrated and set correctly.  I agree, there is something wrong with the drone/DJI go app itself and needs to be fixed.  This is no cheap drone!

These discrepancies are common, and I ignore them since I tend to fly above 60 feet all the time.  I have seen many videos though of guys flying their P4 only a few feet off the ground or water.  

My assumption is that the P4 uses the ultrasonic sensor under 30 feet.  Is that accurate?
When the P4 flies below 30 feet, then the ultrasonic reading take precedence?

I also hope they leave it as is, instead of using some smart code which will force the readings to be the same as the ultrasonic;(to make people happy). I prefer reality, instead of fuzzy logic.

I've noticed my P4 creeps downward in height as well at low hovers.  Apple Air Tab 2 + cellular connection.

I usually pop it up to about 12-15 feet, then fiddle with the camera settings like exposure (Can't do that in tall take-off grass.), white balance, photo/movie slider, color, etc. only to look at it an see it at eye level of 6 feet and slowly dropping.  Sort of disturbing.

Mine struck the ground and broke 2 props. I assumed i was high enough cos it said i was at 10meters. I had only had it a week and was flying with an iphone 5s on a bright day and couldnt see how low i actually was as i was in a the next field, past a hedge. Ive since have bought an ipad mini 2 for better visibility. My worry now is what to set minimum safe height for rth to if the sensors arent that accurate. to just say "the readings wont be correct" doesnt justify having a false reading displayed.

MD_Icarus Posted at 2016-9-11 00:57
These discrepancies are common, and I ignore them since I tend to fly above 60 feet all the time.  I ...

Maybe DJI could add an option to be able to reset the altitude using the ultrasonic sensors when the machine is within 10m of the home point instead of actually having to land and shut off the motors.

I just unboxed my new one today. I did no calibration as I wasn't plan on flying just registering, setting up, and getting familiar with the app and the drone. After updating to the most recent firmware,  indoors on the floor the App height was reading 7 feet off the ground using a Galaxy Note S 4 phone! Our barometric pressure was 29.99 in. at the time.

since I started this post I see the replies of DJI P4 owners are starting to pile up. apparently nothing is being done because I've also been in direct contact with DJI through phone and email as well. hopefully others can contact DJI directly and express their concerns.

rpmurph83 Posted at 2016-9-26 15:06
since I started this post I see the replies of DJI P4 owners are starting to pile up. apparently not ...

Meh, it is either a sign that DJI are working on it, and they will never tell you so, or they are ignoring it, and they won't tell you either. In other words, anytihng could be happening.

KM5RG-Robert Posted at 2016-8-24 06:45
I have seen similar with My P3A. A couple things. First if you land and shut off the motors, it shou ...

Don't wait to long before taking off. Changes in air pressure might confuse the barometric system while the bird is still on the ground.
E. g. when I'm out with my S800 EVO and do a mission with UgCS, the groundstation software will tell me to power off and on the aircraft to reset barometric readings.

On almost each flight I have more than 10 meters difference between takeoff height (always 0) and landing height. The more I go up and down during a flight, the greater the difference is !

Ulysse Posted at 2016-9-26 06:52
On almost each flight I have more than 10 meters difference between takeoff height (always 0) and la ...

I've noticed the exact same thing as well

rpmurph83 Posted at 2016-9-28 22:36
I've noticed the exact same thing as well

Recently I purchased a Phantom 4 Pro and have been quite horrified to find the same altitude errors mentioned above. The error is in the region of about 25 feet in the wrong sense. i.e. if for example flying a FlyLitchi Waypoints mission with a waypoint set at 50 feet it will actually pass it at 25 feet. This has already very nearly been disastrous on several occasions. Does anyone know of any way of re-calibrating the altimeter?

fans5c1aafb6 Posted at 2017-3-5 21:47
Recently I purchased a Phantom 4 Pro and have been quite horrified to find the same altitude errors mentioned above. The error is in the region of about 25 feet in the wrong sense. i.e. if for example flying a FlyLitchi Waypoints mission with a waypoint set at 50 feet it will actually pass it at 25 feet. This has already very nearly been disastrous on several occasions. Does anyone know of any way of re-calibrating the altimeter?

Nope, you cannot calibrate the altimeter.

Yeah, I think all of us P4 owners have the same problem and DJI won't admit it nor will they do anything about it.  As long as these things sell and they can keep their cash flow turning, they don't care.  Why, they will even not tell you the truth should you phone in!  
Yeah, I know.  
But try it sometime.  
Jim
WA5TEF